Blueberry Peach Cast Iron Crisp

Name: Blueberry Peach Cast Iron Crisp
Ingredients: 1/2 cup quick or old-fashioned oats; 1/3 cup dark brown sugar; 1/4 cup all-purpose flour; 1/4 cup sliced almonds; 4 tablespoons unsalted butter, room temperature; 1/2 teaspoon baking powder; Pinch kosher salt; For filling:; 2 pounds sliced peaches; 1 pint fresh blueberries; 1/2 cup dark brown sugar; 2 tablespoons all-purpose flour; 2 teaspoons vanilla bean paste; 1 lemon, zested